title: Low expression of N-myc downstream-regulated gene 2 in oesophageal squamous cell carcinoma correlates with a poor prognosis.
abstract: BACKGROUND
  It is currently unclear whether a correlation exists between N-myc downstream-regulated gene 2 (NDRG2) expression and oesophageal squamous cell carcinoma (ESCC). The aim of this study was to examine the underlying clinical significance of NDRG2 expression in ESCC patients and to investigate the effects of NDRG2 up-regulation on ESCC cell growth in vitro and in vivo.
  
  
  METHODS
  Immunohistochemistry was used to determine the level of NDRG2 expressions in ESCC tissue, which was then compared to specific clinicopathological features in the patient and tissue specimens. Factors associated with patient survival were analysed. Moreover, the effects of up-regulating NDRG2 expression on the growth of an ESCC cell line were examined by MTT, colony formation, DNA replication activity and nude mouse model assays.
  
  
  RESULTS
  Notably low expression of NDRG2 in ESCC patients was inversely associated with clinical stage, NM classification, histological differentiation and patients' vital status (all P < 0.05). ESCC patients expressing high levels of NDRG2 exhibited a substantially higher 5-year overall survival rate than NDRG2-negative patients. Furthermore, NDRG2 over-expression reduced the proliferation, colony formation and DNA replication activity in ESCC cells, as well as inhibiting the growth of ESCC cells in vivo.
  
  
  CONCLUSIONS
  The present experiments demonstrated that NDRG2 may be a diagnostic and prognostic marker in patients with ESCC, and up-regulation of NDRG2 might act as a promising therapeutic strategy for aggressive ESCC.
authors.affiliation: Department of Interventional Radiology, Tangdu Hospital, The Fourth Military Medical University, No.1 Xinshi Road, Xi'an 710038, Shaanxi, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Cao
authors.forename: Guozheng
authors.initials: G
authors.lastname: Yu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Lu
authors.forename: Juliang
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D004938:Esophageal Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D014183:Transplantation, Heterologous; D025521:Tumor Suppressor Proteins / Q000032:analysis / Q000096:biosynthesis*
chemical_list: D014408:Biomarkers, Tumor; C466228:NDRG2 protein, human; D025521:Tumor Suppressor Proteins